Device for holding a door open with permanent magnet actuated ball valve affecting hydraulic cylinder

Abstract

A hydro-magnetic door hold open device. A piston on a piston rod is slideably mounted in a cylinder that is mounted eccentrically inside a housing. The piston rod extends out of the housing and connects to a hingedly mounted door so that opening or closing of the door effects reciprocation of the piston within the cylinder. Both the housing and the cylinder within it are filled with hydraulic fluid. A ball valve positioned forwardly of the piston is confined within a valve chamber that has three seats; the inner cylinder is provided with apertures on the rearward side of the piston and forwardly of the valve chamber so that the ball valve is carried by the fluid into either of two of the seats attendant piston advancement or retraction and maintained in such seat by a pressure differential established in the fluid by the travel of the piston. A magnet external to the housing unseats the ball valve from either of the two seats and positions it in the third seat and this allows free swinging of the door when the door handle is manipulated.

Now that the invention has been described, what is claimed is: 
     
       1. A device for holding a hingedly mounted door open in any preselected position, comprising: a cylindrical, hollow housing member;   a fixed position cylindrical member;   said cylindrical member eccentrically mounted within said housing member and abuttingly engaging an interior sidewall of said housing member;   a magnet mounted externally of said housing member and moveable into and out of abutting relation to said housing member responsive to manipulation of a door handle;   said magnet positioned relative to said housing member in a position closest to said cylindrical member mounted within said housing member;   a ball valve member;   a valve chamber for retaining said ball valve member;   said valve chamber being fixedly positioned within said cylindrical member at a first end thereof and being positioned in the magnetic field of said magnet when said magnet abuts said housing member;   said valve chamber defining three distinct seats into which said ball valve member may seat;   hydraulic fluid filling said housing member, said cylindrical member and said valve chamber;   a piston slideably mounted within said cylindrical member;   a first aperture formed in said cylindrical member at a first end thereof and a second aperture formed in said cylindrical member at a second, opposite end thereof;   said piston and said valve chamber being positioned intermediate said first and second apertures; and   means for connecting said piston to the door to be locked so that swinging of said door effects travel of said piston within said cylindrical member.   
     
     
       2. The device of claim 1, wherein said means for connecting said piston to the door includes a piston rod to which said piston is mounted, said piston rod having its non-piston carrying end extending out of said housing member and being connected to a preselected part of said door so that swinging of said door translates into slideable motion of said piston within said cylindrical member. 
     
     
       3. The device of claim 2, further comprising a pivotally mounted rocker arm member having a pair of laterally extending arms, said magnet mounted to a first one of said arms and a door handle connected to a second one of said arms so that operation of said door handle effects pivoting of said rocker arm and hence movement of said magnet toward and away from said housing member. 
     
     
       4. The device of claim 3, wherein said valve chamber defines a first seat positioned in proximity to said magnet, a second seat positioned in proximity to said piston, and a third seat positioned diametrically opposite said second seat.